Initially, the organisers -- The Muslim Association of Britain -- appeared to struggle to keep order as people flocked into the square from a march which started at Hyde Park.

Eventually, they managed to clear the essential area of the square to let politicians speak on behalf of their cause.

Veteran former Labour MP Tony Benn told the crowd: "This is one of the largest demonstrations I have ever seen here."

He added: "Those who come here to support the Palestinians here today form the overwhelming majority of the population of the world.

"We are demonstrating to the right of the Palestinians to be given their own state. We are demonstrating against what President Bush called `a crusade' against the Muslim world."

A Scotland Yard spokesman told the Press Association that that between 10,000 and 15,000 people had attended the demonstration. The organisers put the figure at more like 30,000.

A spokesman for the Muslim Association of Britain condemned the few incidents of flag-burning that had taken place during the protest.

He said: "When you have thousands of people at such an event, there is always going to be a minority who you cannot control.

"When people chant `jihad' it means `struggle', it does not mean `war'. It means the struggle in the name of your god.

A pro-Palestinian protester waves a flag during the rally

"It is the youth that don't yet know the true meaning of the word, and they tend to get a bit excited just as a large crowd does at a football match.

"We do not believe in the burning of any flag. If there are people burning the American flag, then we are against that and it is the minority of people, not the majority."

Labour MP Jeremy Corbyn said: "This is a demonstration by thousands of British people, Muslim and non-Muslim, demanding peace and the establishment of a Palestinian state and withdrawal by Israeli forces.

"And the message to Tony Blair is now clear, he must stop speaking on behalf of George Bush and instead on behalf of peace and justice in the Middle East."